Update: scroll down for pics
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I have a jdm d15b vtec in my cx hatch,
stock engine.
running a jackson racing supercharger (6-7psi)

heres what happened:
Hmm, ok so I was driving around tonight,
and my cel came on. I pulled over and checked it, it said code 10,
didnt know off the top of my head what that was but I remembered it might be the o2 sensor..

So anyways the car was driving just fine, had a cel but felt great..
so I'm driving home and I forgot about the cel.
Was going pretty fast, like 120 and my engine cuts off

I coast off the freeway and pull over, pop the hood, it smells alittle odd,
like burning something(maybe plastic or rubber..) but visually nothing wrong,
no leaks or anything.
coolant overflow is at its usual level.
no signs of smoke.

I start it back up and it takes a while to start up and runs REAL rough,
sounds NASTY, like as if it has a huge cam or something, but it runs.
so I creep home real careful.
I check out the exhaust and no smoke whatsoever, its clean..

check the CEL again, still code 10.
SO next day I come to find out that one of the wires off my IAT broke off, which is bad because part of my fuel management is the JR map controller, it taps into the IAT wiring to trick the ecu into giving more fuel..

I did a compression test, and found this..
compression test results:
1 190
2 180
3 40
4 175

and the plug from cyl #3


Drove the car around some today,
it sounds like ---- and runs kinda rough, but it drives..
doesn't leak, and didn't notice any smoke(maybe a tiny bit but its hard to tell).

So could this be anything but a blow motor?
coolant overflow is at normal levels and no oil in the coolant..

 

No smoke at all? Hmmm. I don't know much about the JR management systems, but it almost sounds like blown ringlands in your #3 cyl. My buddies car did the same thing. It drove fine and still had plenty of power. We thought the rings were fried, but when we removed the piston, the ringlands just fell to the floor

 

ineteresting,
how did his car sound at idle?
mine sounds like it has a big cam in it now.

I'm trying to figure out whether I should swap in
another d15b($370) or rebuild this one...

how was his block after that?
you guys think mine'll be alright?

 

pop the head off and check it out

 

yeh, I can't.
car still drives and i might have to drive it somewhere.

 

#3 piston is fucked. You can probably save the block and just replace the piston. Don't forget to post pictures of the busted *** piston.
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Yeah, his car did idle a little funny but it still ran fine. The only reason we knew his had something to do with the piston was because of the compression test. But, all we did was put a new piston and new set of rings in and he was driving that thing the same day. Didn't do any damage to the block/ sleeves.

 

yeah I'm very curious to see what's going on in there!

if only I had some kinda fiber optic camera I could stick down there, haha.
Well I can see some of the piston, at least i know a .75" square of the piston is a-ok !!

 

if you take of fhte head you will still not be able to tell if the ringlands are broken unless they scuffed up the cylinders walls. which mine did once...

otherwise take the pan off the pop out the #3 piston and look.

once you do that i would suggest taking them all out and honeing the cylinders and re-ringing it. replace bearings if needed. the end

 

something with your piston is definintly fucked. Pull the pistons out or just buy a new block for cheap :P